Automatically-variable flexible suspension for vehicles



Jan 10, 1928. 1,656,074

J. POYET AUTOMATICALLY VARIABLE FLEXIBLE SUSPENSION FOR VEHICLES Filed Jan.26. 1925 2 Sheets-Sheet l J. POYET AUTOMATICALLY VARIABLE FLEXIBLE SUSPENSION FDR VEHICLES Filed m. 26., 1925 2 Sheets-$heet 2 P P, P P

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Patented Jan. 10. 1928;

PATENT OFFICE.

JACQUES POYE'I, OF LEVALLOIS-PERRET, FRANCE.

AUTOMATICALLY-VARIABLE FLEXIBLE SUSPENSION FOR VEHICLES.

Application filed January 26, 1825, Serial 1T0. 4,912, and in France January 81, 1994.

The suspension of a vehicle, and particularly that of an automobile vehicle, is a function of its period of oscillation which increases with the load and the flexibility. A

U good suspension, under diflerent loads which it is adapted to support, should have periods of oscillation included between a maximum limit and a minimum limit. But for a vehicle under consideration the flexibility of M "the suspension remaining constant, the differences in load alone intervene and they may lead to such variations of the period of oscillation that it frequently becomes impossible to remain within these limits; this dislll advanta e becomes more noticeable when the vehicle is lighter and the variations of the load are greater.

ln these latter cases, in particular with a suspension of slight flexibillty, a vehicle may ml be sufiicientl well suspended under a total load whilst ing badly suspended undera partial load.

With a suspension of great flexibility the "vehicle may be well su ended with a partial load but not so well un er a total load, but a vehicle thus suspended has numerous disadvantages of which the princi al are: the raising of the centre of gravity y reason of the increase and of the loss' of movement we under load and the'increase of vibration due to the bad equilibrium of the vehicle the bad condition of the road, the vehicle tending to set when turninglilexaggerated movements of w; and pitc 'ng; a relatively considerable ifierence between the hei ht of the veliicle when emp and the heig t of the same vehicle updera ll load.

The present invention has for its object to these disadvantages by varying the crease ofv-load, this result being obtained by the application of general means, which con- M sist in varying, by the action of the extenclan of a spring weighed down under the 3 -lcad,the ratio of a reducing system interd between the wheel and the spring. This reducing system with variable reduction may be carried out in various ways and more particularly by means ofa lever which supports the wheel at one of its ends and may oscillate freely on the chassis at its other end, the spring bearing 11 on the lever at an intermediate oint of this latter and the point of support eing capable of moving on the said lever, by reason of the provision of a roller or any other device enabling free movement, in such a manner that when the spring extends when being weighed down under the influence of the load, the said intermediate point will move on the lever which causesa variation of the ratio of the arms'of the lever. a

In the accompanying drawing there are .68 illustrated in side elevation, in a manner entirel diagrammatic and solely by way of examp e, two methods of construction of the invention applied to the rear spring of an automobile vehicle.

Figure 1 shows a simple method of construction wherein the end of the spring bears directly on the reducing lever.

Figures 2, 3 and 4 are diagrams showin respectively the variations of the flexibility in the case of a suspension of constant flexibility, of a suspension of which the flexibility varies in proportion to the weight (arrangement of Fi re 1) and of a suspension of which the flexibility varies according to a lawarbitrarily chosen (device according to F1ure 5).

inally Figure 5 is a similar view to Fig ure 1 showing a method of construction of the invention wherein the end of the sprin bears upon inclines of suitably determin outline.

In the most simple form of construction of the invention, form of construction which is shown in Figure 1, the lever 1 can-oscillate at one of its ends about an axis a secured to the chassis 2and carries at its other and b the A spring 4, which in this form'of construction is in the form of an arc of a circle, is secured to the chassis 2 and bears at its free end at a point a on the lever.

The pomtion, at rest, of the point of en port a is suitably chosen according to t a ratio of reduction which it is desired to obtain for a given position of the chassis 2 in relation to the wheel 3.

, of the lever is equal to On the other hand the flexibility F of the whole depends upon the ratio of the arms of the lever and on the flexibility f of the spring 4 according to the equation The operation of the device will be readily understood. When the wheel 3 and the chassis 2 move towards one another, either under the action of a supplementary load on the chassis 2 or by the action of a shock on the wheel 3, the lever 1 oscillates about the axis a and will occupy a position 1 relatively to the chassis 2, weighing down the spring 4 on the free end of which it rests.

The flexure of the spring 4 is in the form of an arc of dimensioning curvature. the chord of which are increases and the free end of the spring 4 moves along the lever, from the position 0 to the position 0 for which ac a0.

lever remaining thelsame the ratio of the arms of the levers becomes ab ac ac The flexibility F of the spring 4 remaining constant the flexibility F of the whole in the new position has become whic scribed and shown solely by way of examplemay also be carried out with one or more springs difierent to that shown, for example one or more complete springs acting on the lever by their mid int and secured to the chassis at their en s, as also by means of springs arranged in any other manner.

The reducing device may also comprise either a combination of levers or any other members of suitable shape and of suitable number the essential characteristic of the invention residing in the fact that the weighing down of the spring under the action of the load or shock actuates and causes the reduction of the reducing device, interposed between the wheel and the spring, to be varied, this variation being adapted to be efiected and in a direction. andto a value in accordance with the result it is desired to obtain.

It is thus possible, in accordance with the invention to vary the flexibility of the spring according to any law. This result is obtained by means of the device shownin Figure 5. In this method of construction of the invention the end 0 of the spring 4, instead of bearing directly upon the reducing lever l bears upon a cam 5 which may for example be formed of two slopes of suitable outline. By a judicious choice of this outline a variation of the flexibility which ma be desired can be obtained.

he diagrams of Figures 2 to 4 show by way of example the manner in which the flexibility of the suspension sprin of the vehicle may be varied. In these iagrams the loads supported are indicated by the abscissae P, P, P", P; the flexibilities i 13 indicated on the ordinates F, F, F,

Figure 2 shows the case of an ordinary suspension with constant flexibility; the diagram shows that in this case the flexibility does not vary with the load supported.

F gure 3 shows the variation obtained with the device of Figure 1; in this case the The length ab of the long arm of the.

flexibility varies in a uniform manner inversely to the load.

Fi re 4 shows an example of the result may be obtained with the device in Figure 5 b choosing for the material 5 suitable out ines; it will be seen that it is thus possible to give to the sus ension a constant flexibility between A an E (that is to say for a load included between P and P) then a flexibility which rapidly decreases between B and C (that is to say for loads included between P and P), finally the flexibility decreasing still more re idly between 0 and D (for loads include between P. and P kctbis last rapid variation preventing the dy from ressing hard even in the case of a vehicle which is considerably over-loaded.

In the form of construction of the invention shown in Figure 5 the ringassumes the particular shape indica on the drawing; it is secured by means of flanges to a member 7 6 also provided with the axis a of oscillation of the lever 1. It will be understood that the invention is not limited to the particular t pe of spring shown in the drawings. T e cantilever spring shown may be replaced by a spring with blades supportin at its centre a collar fitted with a roller, t is latter bearing and sliding on the part forming the cam of the reducing lever.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is 1. In a device for varying the flexibility of the suspension of a vehicle the combination comprising a chassis, a suspension with the roller at the end of the spring so as spring composed of superposed blades of to vary the flexibility of said sprm in diiferent lengths, the larger end of said aeeordanee with the loading of the vehie e. spring being attached to said chassis, a 2. A device aecordingtoclaim 1, the flexi- 5 roller carried at the thin end of said spring bility constant for a given range, a lever he, one end pivoted to said then d for a van range, and then chassis, a ton wheel rotatabl carried by decreasing more rapi y for another given the other end of said lever, an a'eam inelnrange. ber carried by said lever intermediate of its W ends, said cam being adapted to nae-operate JACQUES POYET. 

